NEW YORK (CNN) -- Former White House counterterrorism expert Richard Clarke accused the Bush administration on Tuesday of going on the offensive against him to "divert attention from the truth" that the administration did "virtually nothing about al Qaeda prior to September 11, 2001."

President Bush, however, said his administration would have acted if he'd known of a pending strike by the terror group.

"[CIA Director] George Tenet briefed me on a regular basis about the terrorist threats to the United States of America," the president said.

"And had my administration had any information that terrorists were going to target New York City on September 11, we would have acted."

But Bush did not comment specifically on Clarke's charge that the administration wrongly focused on Iraq after the 9/11 attacks. In his book "Against All Enemies," Clarke asserts that Bush sought to connect Iraq to the attacks, even though there was no evidence of any such connection.

Clarke defended himself Tuesday on CNN's "American Morning."

"The White House is papering over facts, such as in the weeks immediately after 9/11, the president signed a national security directive instructing the Pentagon to prepare for the invasion of Iraq, even though they knew at the time -- from me, from the FBI, from the CIA -- that Iraq had nothing to do with 9/11," Clarke said.

White House spokesman Scott McClellan said Tuesday that Clarke never mentioned his concerns about the administration's strategy, even as he left the White House.

"There was no mention of the grave concerns he claims to have had on the war on terrorism or what we were doing to confront the threat posed by Iraq, by the former regime," McClellan said.

Clarke is a 30-year White House veteran, having served Presidents Reagan, George H.W. Bush and Clinton before taking on his role in the current administration.

He referred to Bush's own comments to Washington Post reporter Bob Woodward, author of "Bush at War," in which the president said he "didn't have a sense of urgency" about Osama bin Laden or al Qaeda.

"They're trying to divert attention from the truth here," Clarke said. "And they've got all sorts of people on the taxpayers' rolls going around attacking me and attacking the book and writing talking points and distributing them to radio talk shows and whatnot around the country."

Senior administration officials told CNN that President Bush personally signed off on the strategy to aggressively rebut charges by Clarke.

It's not the first time the Bush White House has gone on the offensive over critical comments by a former insider. Top administration figures were active in rebutting allegations in a book by former Treasury Secretary Paul O'Neill but not with the same energy.

Officials said the different approach stems from Clarke's potentially explosive charge that the 9/11 attacks could have been prevented if Bush and other leading figures in the administration had taken a more urgent interest in the al Qaeda threat.

On Monday, Vice President Dick Cheney and national security adviser Condoleezza Rice made various news media appearances defending the administration, while other administration officials did the same in news conferences.

Rice, whom Clarke says ignored his memo requesting an "urgent" meeting on the al Qaeda threat in January 2001, accused Clarke of "retrospective rewriting of history."

"To somehow suggest that the attack on 9/11 could have been prevented by a series of meetings -- I have to tell you that during that period of time, we were at battle stations," she said.

Cheney told conservative talk show host Rush Limbaugh: "The only thing I can say about Dick Clarke is he was here throughout those eight years going back to 1993 and the first attack on the World Trade Center, in [1998] when the [U.S.] embassies were hit in east Africa, in 2000, when the USS Cole was hit.

"The question that has to be asked is, 'What were they doing in those days when he was in charge of counterterrorism efforts?'"

Clarke answered Cheney's question Tuesday. During the Clinton administration, he said, al Qaeda was responsible for the deaths of "fewer than 50 Americans," and Clinton responded with military action, covert CIA action and by supporting United Nations sanctions.

"Contrast that with Ronald Reagan, where 300 [U.S. soldiers] were killed in [a bombing attack in Beirut,] Lebanon, and there was no retaliation," Clarke said. "Contrast that with the first Bush administration where 260 Americans were killed [in the bombing of] Pan Am [Flight] 103, and there was no retaliation."

"I would argue that for what had actually happened prior to 9/11, the Clinton administration was doing a great deal," Clarke said. "In fact, so much that when the Bush people came into office, they thought I was a little crazy, a little obsessed with this little terrorist bin Laden. Why wasn't I focused on Iraqi-sponsored terrorism?"

On Limbaugh's program Cheney said Clarke "wasn't in the loop" on major decisions and may hold a personal grudge against Rice. He said Clarke may have wanted a more "prominent position." Clarke has denied any such motive for his book.

Clarke called Rice's contention that he never offered a plan against al Qaeda "counterfactual." "We presented the plan to her ... before she was even sworn into office," Clarke said.

Rice has characterized as "ridiculous" Clarke's statement in his book that she seemed unaware of al Qaeda until he told her about it.

"I wasn't born yesterday when Clarke briefed me," she said Monday. "This wasn't an issue of who knew about al Qaeda, but what we were going to do about al Qaeda."